Coastal cities surrounded by hills or mountains are prime candidates for summer smog. Winter smog is essentially created by the excessive use of fossil fuels to heat up homes and buildings. Winter photochemical smog forms during extreme weather conditions, particularly during the height of winter. This is because during extremely cold conditions, populations of cities which have a large number of hearth-heated homes use coal or other combustibles that generate considerable amounts of smoke and pollutants.
These air pollutants appear at the lower levels in the atmosphere. The cold and moist air retains the emissions for a longer time through the chemical reactions that take place at a slower rate.
Cities boxed in by surrounding higher elevations, which experience heavy snowfalls, face smog regularly. Deyanda Flint has been writing professionally since How Is Photochemical Smog Formed?
Products like ozone, aldehydes, and peroxyacetyl nitrates are called secondary pollutants. The mixture of these primary and secondary pollutants forms photochemical smog. Both the primary and secondary pollutants in photochemical smog are highly reactive.
These oxidizing compounds have been linked to a variety of negative health outcomes; ozone, for example, is known to irritate the lungs. Smog can also affect areas of the country that are sunny less frequently, such as New York City.
In fact, most major cities have problems with smog and air pollution. Boundless vets and curates high-quality, openly licensed content from around the Internet.
It is visible as a brown haze, and is most prominent during the morning and afternoon, especially in densely populated, warm cities. Photochemical smog forms from a complex process, however the source of it is quite apparent. The largest contributor is automobiles, while coal-fired power plants and some other power plants also produce the necessary pollutants to facilitate its production.
Due to its abundance in areas of warmer temperatures , photochemical smog is most common in the summer. It forms in the morning when a tremendous number people are driving their vehicles to work. Nitrogen oxides produced in the car engine are introduced into the atmosphere, which may combine with water to form nitric acid or react with sunlight to produce singular oxygen atoms, which then combine with molecular oxygen to produce ozone.
Due to the direct production of it by vehicles, the smog forms over cities where many people may encounter its adverse health effects. Hotter days mean more photochemical smog, especially in the densely populated cities such as those mentioned above.
As more and more urban populations arise around the globe, this problem is only expected to increase. To spread awareness on the dangers of pollution and its mitigation methods, the Delhi Pollution Control Board conducts routine awareness programs and workshops.
Punitive measures include those taken after or during the crisis. Perhaps the most positive action of the government was formation of the SAFAR air quality index, which combines five of the most pressing pollutants into a single air quality index AQI. This ranges from good to severe and can help in policy formulation as well as precautionary measures. The short-term policies include implementing odd-even scheme, sprinkling water on trees and roads to prevent dust along with vacuuming the roads and banning gensets and construction activities.
Immediate decisions such as school holidays for primary children have also been taken, soon after the rise of pollution levels. Awareness programmes regarding ways to reduce pollution by lifestyle changes and mitigation measures at a personal level, such as growing more indoor plants or wearing of proper masks are also run by the government and various NGOs for public benefit. In the Union budget, a special scheme was announced to subsidize farm equipments for Haryana, UP and Punjab to reduce problem of stubble burning.
The odd-even scheme deserves special mention and analysis because it was a radical and innovative immediate remediation measure to the alarming smog situation in Delhi. The scheme called for restriction on certain class of non-commercial vehicles during peak hours based on their license plate numbers, whereby they were to ply alternatively. But this decrease was nothing dramatic due to interference from other factors, mainly metrological.
However, reduction in number of vehicles plying on the road, traffic, and travel time was widely appreciated. One more novel scheme tested by the government was an anti-smog gun, the prototype of which was tested by the Delhi government at Anand Vihar, one of the most polluted locations in the capital.
The concept is that the gun will shoot a mist of high pressure water into the air, which will capture and immobilize pollutants and particles, making them settle on the ground later. A special mention must be made about commercialization of smog and pollution and what one can do as an individual to mitigate the risks.
As the health effects of outdoor and indoor air pollution are better understood now, commercial market records growing number of products for the improvement of indoor air quality. Air purifier is a device which removes contaminants from air and improves indoor air quality by employing several types of successive filters; pre filter, activated carbon, HEPA, photolytic, etc.
Various kinds of air purifiers are available in market depending on the shape, volume, level of protection offered and price. In case of masks, a series of pollution masks like N, N are available in the market depending on the efficiency to filter airborne particles from 95 per cent to 99 per cent respectively, costing anywhere from around Rs to Rs 1, However, it is to be noted that prolonged study measuring the effectiveness and long-term utility of air purifiers and masks have not been done and the prospects of such improved personal devices by no means suggest "to continue and pollute more and more".
It is evident that most of the measures taken against smog and pollution are punitive and ad hoc in nature and address the symptoms and not the root cause of the problem. In the case of indoor pollution, more analysis is needed to assess its long-term effects. To find a permanent and sustainable solution to air pollution and smog, there needs to be a synergy between all levels of policy formulation and implementation from the Delhi government, Centre, National Green Tribunal, judiciary, expert agencies and most importantly people.
Also, opinions and considerations from all sections of the society, especially experts of agriculture, environment, chemistry, industry etc. Comprehensive studies, evaluating the pros and cons of personal mitigation devices for a permanent solution to air pollution crisis of Delhi, need to be conducted with a holistic and interdisciplinary approach.
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